/* $Id: dlt_plugins-int.h 1841 2007-04-26 03:43:14Z aturner $ */

/*
 * Copyright (c) 2006-2007 Aaron Turner.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the names of the copyright owners nor the names of its
 *    contributors may be used to endorse or promote products derived from
 *    this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 * IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
 /*
  * Internal data structures and helper functions for DLT plugins
  * Should not be available outside of the plugin framework
  */


#ifndef _DLT_PLUGINS_INT_H_
#define _DLT_PLUGINS_INT_H_

#include "tcpedit-int.h"
#include "tcpr.h"
#include "dlt_plugins.h"
#include "tcpedit_stub.h"


/* 
 * Plugin Requires/Provides Bit Masks 
 * If you add any fields to the provides/requires bitmask,
 * then you also must add appropriate records for
 * tcpeditdlt_bit_map[] and tcpeditdlt_bit_info[]
 * in dlt_plugins.c
 */
enum tcpeditdlt_bit_mask_e {
    PLUGIN_MASK_PROTO         = 0x01,
    PLUGIN_MASK_SRCADDR       = 0x02,
    PLUGIN_MASK_DSTADDR       = 0x04
};
typedef enum tcpeditdlt_bit_mask_e tcpeditdlt_bit_mask_t;

/* Union of all possible L2 address types */
union tcpeditdlt_l2address_u {
    u_char ethernet[ETHER_ADDR_LEN]; /* ethernet is 6 bytes long */
    u_int8_t c_hdlc;                 /* Cisco HDLC is a single byte */
};
typedef union tcpeditdlt_l2address_u tcpeditdlt_l2address_t;

/* What kind of address is the union? */
enum tcpeditdlt_l2addr_type_e {
    NONE,           /* DLT has no L2 address */
    ETHERNET,       /* support ethernet */
    C_HDLC,         /* Cisco HDLC uses a 1 byte addr which has only two values 0x0F & 0xBF */
};
typedef enum tcpeditdlt_l2addr_type_e tcpeditdlt_l2addr_type_t;

/* src or dst mac */
enum tcpeditdlt_mac_type_e {
    SRC_MAC,
    DST_MAC
};
typedef enum tcpeditdlt_mac_type_e tcpeditdlt_mac_type_t;

/* MAC address buffer length */
#define MAX_MAC_LEN 10

/* 
 * Each plugin must fill this out so that we know what function
 * to call from the external API
 */
struct tcpeditdlt_plugin_s {
    u_int16_t dlt;  /* dlt to register for */
    char *name;     /* plugin prefix name */
    struct tcpeditdlt_plugin_s *next; /* next in linked list */
    int requires; /* bit mask for which fields this plugin encoder requires */
    int provides; /* bit mask for which fields this plugin decoder provides */
    int (*plugin_init)(tcpeditdlt_t *);
    int (*plugin_cleanup)(tcpeditdlt_t *);
    int (*plugin_parse_opts)(tcpeditdlt_t *);
    int (*plugin_decode)(tcpeditdlt_t *, const u_char *, const int);
    int (*plugin_encode)(tcpeditdlt_t *, u_char **, int, tcpr_dir_t);
    int (*plugin_proto)(tcpeditdlt_t *, const u_char *, const int);
    int (*plugin_l2len)(tcpeditdlt_t *, const u_char *, const int);
    u_char *(*plugin_get_layer3)(tcpeditdlt_t *,  u_char *, const int);
    u_char *(*plugin_merge_layer3)(tcpeditdlt_t *, u_char *, const int, u_char *);
    tcpeditdlt_l2addr_type_t (*plugin_l2addr_type)(void);
    u_char *(*plugin_get_mac)(tcpeditdlt_t *, tcpeditdlt_mac_type_t, const u_char *, const int);
    void *config; /* user configuration data for the encoder */
    
};
typedef struct tcpeditdlt_plugin_s tcpeditdlt_plugin_t;

#define L2EXTRA_LEN 255 /* size of buffer to hold any extra L2 data parsed from the decoder */

/*
 * internal DLT plugin context
 */
struct tcpeditdlt_s {
    tcpedit_t *tcpedit;                 /* pointer to our tcpedit context */
#ifdef FORCE_ALIGN
    u_char *l3buff;                     /* pointer for L3 buffer on strictly aligned systems */
#endif
    tcpeditdlt_plugin_t *plugins;       /* registered plugins */
    tcpeditdlt_plugin_t *decoder;       /* Encoder plugin */
    tcpeditdlt_plugin_t *encoder;       /* Decoder plugin */      
                    /* decoder validator tells us which kind of address we're processing */
    tcpeditdlt_l2addr_type_t addr_type;    

    /* skip rewriting IP/MAC's which are broadcast or multicast? */
    int skip_broadcast;
    
    /* original DLT */
    u_int16_t dlt;

    /*
     * These variables are filled out for each packet by the decoder
     */
    
    /* The following fields are updated on a per-packet basis by the decoder */
    tcpeditdlt_l2address_t srcaddr;         /* filled out source address */
    tcpeditdlt_l2address_t dstaddr;         /* filled out dst address */
    int l2len;                              /* set by decoder and updated by encoder */
    u_int16_t proto;                        /* layer 3 proto type?? */
    void *decoded_extra;                    /* any extra L2 data from decoder like VLAN tags */
    u_char srcmac[MAX_MAC_LEN];             /* buffers to store the src & dst MAC */
    u_char dstmac[MAX_MAC_LEN];
};

#endif